Several different experimental methods have been used to
determine coupling strengths. Mark et al.
[1]} used a method based on Stückelberg
interferometry, which gives precise measurements of the energy
difference between the two states. Mark et al.
[2]} used a different method based on integrating
magnetic moment values. This gives absolute energies for the
two states (rather than just the difference between them) but
is now believed to overestimate the coupling strengths in some
cases [3]}, especially for crossings
between states with very different magnetic moments. Some
crossing strengths were also estimated from a Landau-Zener
approach. Lastly, Ferlaino et al.
[4]} have used a method in which
transitions are induced by modulating the magnetic field
[5]}. This is the most precise of the
different methods.
<TABLE>